This invention relates to a chord designating apparatus of an electronic musical instrument, and more particularly an improved apparatus for generating a desired chord by combining a root note and a type of a chord.
A method of designating a desired chord by combining a root note and a type of a chord has been known in conventional electronic musical instruments as a chord designating method in a single finger mode of an automatic bass/chord performance. The following two methods of chord designation have been used. According to one method, in an electronic musical instrument provided with at least three keyboards, i.e., an upper keyboard, a lower keyboard and a pedal keyboard, a root note of a desired chord is designated by a depressed key of the lower keyboard while a chord type such as minor, seventh, or major etc. is designated by depression of a sharp black or natural (white) key of the pedal keyboard or not. This method is disclosed in U.S. Pat. No. 3,844,192, for example.
According to the other method, a root note of a desired chord is designated by a depressed key of a keyboard, for example a lower keyboard, and a type of the chord is designated by a special chord type designating switch (for example, a touch bar type switch) independent of the keyboard is operated. This method is disclosed in U.S. Pat. No. 3,629,481, for example.
The use of a pedal keyboard to designate the chord type is disadvantageous. It necessitates that the instrument have such a keyboard. Furthermore, even in an electronic musical instrument provided with three keyboards, at the time of the chord type designation, the pedal keyboard can not be used for inherent bass tone manual perormance.
The use of a special switch exclusively for the chord type designation is disadvantageous, since providing such a switch increases the manufacturing cost and space. Moreover the performer must simultaneously manipulate a keyboard for designating the root note and a switch device for designating the chord type which is independent of the keyboard.
Alternatively instead of providing a special switch for designating the chord type, a system has been proposed in which when a single key is depressed a major chord is designated, whereas when two or more keys are depressed a minor chord is designated. This method, however, cannot designate such other chord types as the 7th and minor 7th. To obviate this difficulty, the other chord type may be designated according to the number of the depressed keys, for example 3 or 4. This method, however, increases the load of the performer because he must simultaneously depress a number of keys.